1. Technical Field
The technical field relates to a method for establishing a connection between communication apparatuses, particularly over a network such as the Internet, and also relates to a communication apparatus and a server apparatus each involved in such a method.
2. Description of the Related Art
Methods for connecting communication apparatuses each connected to the Internet have been known in the art (e.g., see Japanese Patent Laid-open Publication No. 2003-169075). Japanese Patent Laid-open Publication No. 2003-169075 discloses a connection helper server capable of establishing communications between a requesting terminal and an answering terminal. The connection helper server relays data using connections from the answering terminal and requesting terminal associated with each other, for data transmission and reception.
Among methods for establishing a connection between two communication apparatuses, a peer-to-peer (P2P) method is known. According to the peer-to-peer method, it is possible to transmit and receive data directly between communication apparatuses not through a server apparatus. However, according to the peer-to-peer method, the communication apparatuses should exchange their information with each other via the server apparatus before establishing the connection between the communication apparatuses. In other words, the communication apparatuses should communicate with the connection helper server apparatus before establishing the connection between the communication apparatuses.